Numerous assemblies have been designed to support conventional cables having electrical conductors. U.S. Pat. Nos. 2,058,558, 3,437,742, and 4,727,224 illustrate three such assemblies, each including a body for receiving the cable and a clamping head or jaw secured by a bolt. U.S. Pat. No. 3,633,858 discloses a similar clamping assembly using a leaf spring as part of the clamping member.
These and other supports for conventional electrical cables are typically unsuitable for use with fiber optic cables, however. Because these optical cables lack the strong metallic conductors of standard electrical cables, they are more fragile and easily damaged or crushed. Cable damage can, in turn, degrade the overall effectiveness of the optical fibers as a transmission medium, in many cases necessitating repair or replacement of the damaged section.
U.S. Pat. No. 5,014,941 ("the Sherman patent"), incorporated herein in its entirety by this reference, discusses additional difficulties associated with stringing and supporting fiber optic cables. Among these are mechanical problems in gripping the cables and flexural fatigue resulting from dynamic stresses caused by cable oscillation. Static stresses related to suspending the relatively fragile cable at only selected points along its length additionally contribute to cable fatigue.
The Sherman patent accordingly presents a fiber optic cable support assembly designed to address these difficulties. As described in the Sherman patent, the assembly includes two rigid dielectric body portions defining a central bore. The bore receives a two-piece cushion, which in turn receives and contacts the fiber optic cable. An internally threaded aperture in one body portion permits the assembly to be attached to a structure having a pre-embedded fastener, although the body portion must be repeatedly rotated to attach the assembly to, for example, a utility pole. This rotation makes installing the assembly cumbersome and, obviously, precludes the assembly from receiving the cable until the pertinent body portion is attached to the pole.
The enclosed nature of the assembly disclosed in the Sherman patent dictates use of a fixed diameter bore and cushion. Assemblies designed according to the Sherman patent also require application of grit to the cushion to increase the coefficient of friction between the cushion and cable and thereby reduce cable slippage. Combined, these requirements restrict the flexibility of each particular assembly, effectively limiting its use to a single size fiber optic cable. The enclosed assembly and cumbersome installation requirements also diminish access to the cable for repairs or replacement once installed. Further, the flat surface of the assembly's enlarged boss reduces the surface area available to contact a curved structure (again, such as a utility pole) during installation, decreasing the strength of the connection between them.